Snap-attached case and back of a clock



Jan. 3, 1956 c. H. ARNOLD SNAP-ATTACHED CASE AND BACK OF A CLOCK FiledSept. 25, 1952 Hiram/2:545.

United States Patent SNAP-ATTACHED CASE AND BACK OF A CLOCK CharlesHenry Arnold, Colebrook River, Conn., assignor to The William L. GilbertClock Corporation, Winsted, Conn., a corporation of ConnecticutApplication September 25, 1952, Serial No. 311,443

2 Claims. (CI. 58-53) This invention relates to timepieces in general,and to clocks in particular.

The type of clock to which the present invention relates carries themovement on a rear plate which is secured to and covers the open back ofthe clock case for most facile assembly of the movement with the rest ofthe clock' Usually, the movement-carrying rear plate is secured to theopen back of the clock case by screws which form a rigid connectionbetween the rear plate and clock case, with the result that shock orvibration to which the clock case may be subjected is rather freelytransmitted to the movement. It is for this reason that clocks of thistype become sometimes impaired and even damaged during ordinary shipmentfrom the factory, and they become almost certainly damaged when droppedaccidentally. Further, the task of driving screws into the clock casefor the attachment of the movement-carrying rear plate to the open backof the case has been found laborious and tiresome, especially in thecase of plastic-molded clock cases which are usually provided withcored-out holes in which the screws cut their own threads when beingapplied.

It is an object of the present invention to provide a clock of this typewhich is far more shock and vibration resistant than previous clocks ofthis type, so that the present clock wil hardly become impaired ordamaged in ordinary transit, and will more often than not surviveaccidental dropping Without appreciable damage.

It is another object of the present invention to provide a clock of thistype of which the movement-carrying rear plate is mounted in the openback of the clock case by being simply snapped in place therein, therebynot only eliminating the laborious and tiresome task of applying theplate-attachment screws to the cases of previous clocks of this type,but also saving the cost of these screws.

A further object of the present invention is to provide a clock of thistype of which the entire clock case is somewhat resilient and isdeformed when the movementcarrying rear plate is snapped in placetherein, so that the case will, on its recovery, be interlocked with thesnappedin plate and hold it in place as securely as if the same were anintegral part of the case.

Another object of the present invention is to provide a clock of thistype of which the resilient case is on its inside provided not only witha plurality of relatively deep notches for interlock with themovement-carrying plate, but also with wedge formations which lead tothese notches and which will give readily when the rear plate is forcedthereover into interlock with the notches, thereby requiring only simpleinward pressure against the rear plate at the open case back in order tosnap the former securely in place therein and accurately position themovement in the case without any further attention from the assembler.

It is a further object of the present invention to pro vide a clock ofthis type of which the open back of the clock case is somewhat largerthan the movement-carry- ICC ing rear plate, so that the case will, onthe snap-in application of the rear plate, be resiliently deformedwithout being subjected to appreciable tensile stresses, with the resultthat the snap-in pressure or force to be exerted on the rear plate maybe comparatively moderate.

Another object of the present invention is to provide a clock of thistype of which the aforementioned notches and wedge formations arelocated in the open back of the clock case on only two opposite sidesthereof, so that the case back will, on the snap-in application of therear plate, be momentarily spread in one general direction and permittedto contract simultaneously in a transverse direction, with the resultthat an even more moderate force on the rear plate will snap the same inplace.

it is another object of the present invention to provide a clock of thistype of which the aforementioned notches in the open case back aresufliciently deep to permit substantially complete recovery of the caseto its original shape after the movement-carrying rear plate has beensnapped in place therein, so that the case is not subjected to anyappreciable permanent stresses that could the more readily bring aboutdamage to the case if the clock were dropped accidentally.

Another object of the present invention is to provide a clock of thistype of which the aforementioned notches in the open case back arerelatively short, few in number, and their bottoms are preferablysomewhat spaced inwardly from the case wall, so that the snapped-inmovement-carrying rear plate is throughout the far greater part of itscircumference spaced from the case wall slightly but neverthelesssufliciently to preserve the resiliency of the case to such an extentthat the latter will more often than not withstand even considerableshock or vibration without becoming appreciably damaged, it at all, andwill absorb most of these disturbing forces before they may cause anyappreciable damage to the movement.

it is a further object of the present invention to provide a clock ofthis type of which the case is conveniently and economically formed ofslightly resilient plastic and has relatively thin walls to lend thecase considerable resiliency, with the result that a comparatively smallforce is required to snap the movement-carrying rear plate into the caseback and only a moderate force need be exerted on the case back tospread the same sufiiciently for intended removal from the case of therear plate and the movement thereon for repair or other purposes, yetthe case, with the rear plate snapped in place therein, is fully asrigid as clock cases are required to be.

Further objects and advantages will appear to those skilled in the artfrom the following, considered in conjunction with the accompanyingdrawings.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. l is a reduced front view of a clock embodying the presentinvention;

Fig. 2 a side view of the clock;

Fig. 3 is an enlarged rear view of the clock;

Fig. 4 is a section taken substantially on the line 4-4 of Fig. 3; and

Fig. 5 is a fragmentary rear view of the clock similar to Fig. 3,showing the clock shortly before its final assembly.

Referring to the drawings, and more particularly to Figs. l to 4thereof, the reference numeral 10 designates a timepiece, in thisinstance a clock, which comprises a case 12, a movement 14 carrying atime dial 16, a rear plate 18 and a dial-covering crystal 20. The case12 is slightly resilient and has a front 22 with a bezel 24, an openback 26, and an uninterrupted peripheral wall 28 between front and back.The case 12 may assume any desired shape, and is in this instancegenerally rectangular, leaving the peripheral case wall 28 with top andbottom portions 30 and 32 and opposite side portions 34 and 36. p

The movement 14 may be mechanical or electrical, and is in this instanceindicated in an abbreviated fashion as mechanical (Fig. 4), the primemover being a mainspring 38. The movement 14 has the usual pillar-spacedend plates 4i) and 42, as well as minute and hour hands 44 and 46 on thecustomary arbors. The time dial 16 is suitably mounted on the end plate40 behind the minute and hour hands 44 and 46.

The movement 14 is carried at 47 on the rear plate 18. The movement 14may thus be conveniently preassembled with the rear plate 18, so thatthe former will be quickly placed and correctly located in the case 12on simply mounting the rear plate in the case. In recur"- ance with thepresent invention, the rear plate 18 is mounted in the open back 26 ofthe case by being simply sprung or snapped therein. To this end, thecase 12, and more particularly the peripheral wall 23 thereof, isprovided with a plurality of spaced inner ribs or projec tions 5t) whichare provided with notches 52, respectively, adapted for interlock withthe periphery of the rear plate 18. Each of the ribs 50 is in partformed as a wedge 54 (Fig. 4) which extends axially of the case 12 andascends substantially from the case wall 23 at or near the open caseback 26 toward the adjacent notch 52.

The movement 14 is, in the present instance, of a size to be received inthe case 12 with clearance from the peripheral wall 43 thereof (Fig. 4).The rear plate 18, with which the movement 14 is pie-assembled asdescribed, is mounted in the case 12 by simply forcing it planewise intothe open case back 26. In doing so, the periphery of the rear plate 18will spring or snap over the wedges 54 into interlock with the notches52. The crystal 2t), having been placed in the bezel 24 through the opencase back 26 prior to the snap-in of the rear plate 13, will on thesubsequent snap-in of the latter be engaged by the time dial 16 andsecurely held thereby in the bezel 24.

The rear plate 18 is preferably somewhat smaller than the opening in thecase back 26, and the notches 52 are preferably of such depths that therear plate permits sub stantially complete recovery of the case 12 toits original shape (Fig. 3) after the former has been snapped or sprungin place therein. Accordingly, while the case 12 is only momentarilydeformed, and hence tensioned, during the actual snap-in of the rearplate 18, it is not subjected to any appreciable permanent stressesafter the rear plate has been snapped in place therein.

While the case 12 may be made of any suitable slightly resilientmaterial, such as sheet'metal, for instance, the same is in thisinstance molded of slightly resilient plastic. In order to lendconsiderable resiliency to the case 12 as well as economize in theamount of plastic required for the case, the peripheral wall 28 andpreferably also the front wall 22 thereof are made relatively thin. Themolded case 12 may, at least in the corners of the peripheral wall 28thereof, be reenforced by integral rib formations 60 which terminate inposts 62 that extend to the snapped-in rear plate 18 and serve asabutments therefor. Further, the notched ribs or projections 56, byextending throughout the width of the peripheral case wall 28 for mostfacile and economical molding of the case, further reenforce the latterwithout appreciably detracting from its overall resiliency.

While the rear plate 18 is somewhat smaller in size than the opening inthe back of the case 12 (Fig. 3), it is preferably of a shape similar tothat of this opening so that the snapped-in rear plate willsubstantially cover the open case back 26 and protect the movement 14from dust and other foreign matter.

As shown in Fig. 4, the bottoms of the notches 52 in the ribs 50 arepreferably slightly spaced inwardly from the peripheral case wall 28 sothat the non-interlocked peripheral portions of the rear plate 18 mayhave slight clearance from the peripheral case wall 28 (Fig. 3).Further, the ribs 50 are preferably few in number and their notches 52are relatively short, so that by far the greater part of the peripheryof the mounted rear plate 18 may substantially clear the peripheral casewall 23. As shown also in Fig. 3, the ribs 59 are located on only twoopposite sides of the peripheral case wall 28, in this instance on thetop and bottom portions as and 32 thereof. in having by far the greaterpart of the periphcry of the mounted rear plate 18 substantially clearof the peripheral case wall 28, the case 12 will retain a good deal ofits resiliency, with the result that the case will not only act as avery effective shock absorber for the movement 14, but may itselfwithstand considerable shock or vi bration without becoming damaged. Ifthe instant clock should be subjected to more severe shock, as byaccidentally dropping the same, the case 12, if sustaining any damage atall, will more often than not be damaged much less than a similar caseto which the movement-carrying rear plate is attached by screws asheretofore. Thus, two clocks of the instant type, one with the rearplate snappedin the case and the other with the rear plate screwed inthe case, were repeatedly dropped onto the floor from a height over ayard, with the result that the clock with the snapped-in rear platesustained minor damage to the case but kept running accurately and couldwell be used thereafter despite the damage to the case, while the otherclock was damaged beyond repair, especially insofar as the case wasconcerned.

By providing the ribs 50 on only two opposite sides of the peripheralcase wall 28 as described, and since the rear plate 18 is made somewhatsmaller than the opening in the case back 26, the case 12 willmomentarily be spread in the general direction of the arrow 6-. in Figs.3 and 5, and permitted to contract simultaneously in a directiontransverse thereto, when the rear plate is snapped in place in the case(see particularly Fig. 5). Thus, the case 12, and particularly theperipheral wall 28 thereof, will primarily be resiliently deformed andnot subjected to any considerable tensile stresses when the rear plate18 is snapped in place in the open case back 26, with the result thatonly a moderate force is required to snap the rear plate in place, or toremove the same from the case for repair or other purposes.

Instead of merely forcing the rear plate 13 planewise into the open caseback 26 for its snap-in attachment thereto as described, either the topedge or the bottom edge of the rear plate may first be placed intointerlock with the adjacent pair of notches 52 before the rest of therear plate is forced inwardly into the case back for snapping theopposite edge of the rear plate into interlock with the other pair ofnotches 52. In following this alternative course, the case 12 is lessdeformed momentarily and correspondingly less force is required to snapthe rear plate in place. Further, if it should be contemplated to mountthe rear plate in accordance with this alternative mode, only one of theopposite pairs of ribs 50 need be formed with wedges 54, as will bereadily understood.

The rear plate 18, being preferably made of relatively rigid sheet metalfor the secure mounting thereon of the movement 14, has neverthelessslight spring characteristics by being ofiset at 70 (Figs. 3 and 4). Theslightly springy rear plate 18 not only protects the movement 14 evenfurther from shock or vibration to which the case 12 may be subjected,but also accomplishes somewhat yielding retention of the crystal 20 inthe bezel 24 by the time dial 16.

The invention may be carried out in other specific ways than thoseherein set for without departing from the spirit and essentialcharacteristics of the invention,.and the present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

What is claimed is:

1. A clock comprising a case of slightly resilient material having anopen back, a front with a dial aperture, and an endless peripheral wallbetween front and back, said wall having angularly spaced notched inwardprojections formed in part as wedges, respectively, extending axially ofthe case and ascending substantially from said Wall near said open backtoward said front to the respective notches, and the latter havingbottoms spaced inwardly from the adjacent inner surface of said wall; amovement receivable in said case with clearance therefrom; and amovement-carrying rear plate shaped similarly as, but slightly smallerthan, the opening in said case back, so that the periphery of said platemay be sprung over said wedges into the respective notches for thesecure attachment of said plate to the case with the movement in thelatter and the periphery of said plate slightly spaced from said innerwall surface, said rear plate having an inner web portion on which saidmovement is mounted and which is spaced inwardly from said projectionson said case wall, and an uninterrupted peripheral marginal portionlaterally offset from the plane of said Web portion, thereby lendingspring characteristics to said plate.

2. A clock comprising a case of slightly resilient material having anopen back, a front with a dial aperture, and an endless peripheral wallbetween front and back,

said wall having angularly spaced notched inward projections formed inpart as Wedges, respectively, extending axially of the case andascending substantially from said wall near said open back toward saidfront to the respective notches, and the latter having bottoms spacedinwardly from the adjacent inner surface of said Wall; a movementreceivable in said case with clearance therefrom; and amovement-carrying rear plate shaped similarly as, but slightly smallerthan, the opening in said case back, so that the periphery of said platemay be sprung over said wedges into the respective notches for thesecure attachment of said plate to the case with the movement in thelatter and the periphery of said plate slightly spaced from said innerwall surface, said rear plate having an inner web portion on which saidmovement is mounted and an uninterrupted peripheral marginal portionlaterally offset from the plane of said web portion, thereby lendingspring characteristics to said plate.

References Cited in the file of this patent UNITED STATES PATENTS1,619,674 Kohn Mar. 1, 1927 1,752,651 Porter Apr. 1, 1930 2,012,002Finch Aug. 20, 1935 2,078,476 Whitehead Apr. 27, 1937 2,254,599 CarlsonSept. 2, 1941 2,515,669 Scholl July 18, 1950 FOREIGN PATENTS 404,502Atkins Jan. 18, 1934

